/* 通用重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* 背景和排版 */
body {
  height: 100vh;
  background: linear-gradient(to right, #f6f6f6, #eaeaea);
  font-family: "Helvetica Neue", sans-serif;
  color: #444;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* 顶部链接栏 */
.top-bar {
  width: 100%;
  background: #fff;
  padding: 15px 30px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.05);
  display: flex;
  justify-content: flex-end;
}

.top-bar .links a {
  margin-left: 20px;
  text-decoration: none;
  color: #007BFF;
  font-weight: 500;
  transition: color 0.3s ease;
}

.top-bar .links a:hover {
  color: #0056b3;
}

/* 内容包裹器 */
.wrapper {
  text-align: center;
  max-width: 600px;
  margin-top: 80px;
  padding: 40px;
  background: white;
  border-radius: 20px;
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.05);
}

/* 标题样式 */
h1 {
  font-size: 2.2em;
  margin-bottom: 20px;
}

/* 段落样式 */
p {
  margin: 15px 0;
  font-size: 1.1em;
  line-height: 1.6;
}

/* 圆圈样式 */
.circle {
  width: 80px;
  height: 80px;
  background-color: #ddd;
  border-radius: 50%;
  margin: 30px auto;
  transition: background-color 0.5s ease;
}
.circle:hover {
  background-color: #bbb;
}

/* 页脚样式 */
footer {
  margin-top: 40px;
  font-size: 0.9em;
  color: #999;
}